Heavy teenage cannabis use linked with anxiety disorders

(Medical Xpress) -- Teenagers who smoke cannabis weekly or more are twice as likely as non-users to have an anxiety disorder in their late 20s, even if they stop using, a study of 2000 Victorian teenagers has found.

Those who used frequently in their teens and continued to use on a daily basis at the age of 29 were three times as likely to have an anxiety disorder compared with non- or infrequent users. Those who used minimally in their teens but became daily users in their late 20s were two and a half times as likely to have an anxiety disorder.

But the really striking finding say the authors is the persistent association between frequent teenage cannabis use and adult anxiety disorders up to a decade after cannabis use has ceased.

The relationship between cannabis use and anxiety disorders was present even after the researchers took into account other possible explanations such as mental health problems in their teens or other drug use in their twenties.

The findings, published online in Addiction are based on secondary analyses of a landmark study of nearly 2000 Victorian secondary school students - the 2000 stories cohort, led by Professor George Patton of the Centre for Adolescent Health at the Murdoch Childrens Research Institute in Melbourne. The students have been followed up and interviewed over 13 years, starting in 1992. They were interviewed at six six-monthly intervals during their teens and then again when they were aged 20-21, 24-25, and 29.

Lead author of the analysis, Professor Louisa Degenhardt from the National Drug and Alcohol Research Centre at the University of New South Wales, said that most studies looking at cannabis use and mental health outcomes focus on adolescence and early adulthood. What we are seeing is a persistent association with anxiety disorders over a much longer period.

Given that anxiety is the most prevalent mental health disorder in the Australian population, affecting over 14 per cent of adults in any 12 month period, we need to investigate the findings further because it is highly possible that early cannabis use causes enduring mental health risks.

Professor Patton, lead investigator of the 2000 stories cohort, said that the findings could be explained by lasting changes to brain function caused by introducing cannabis at a time when the brain is developing rapidly. Equally it could be that the very factors which predispose people to use cannabis early also predispose them to common mental health problems.

We know from animal studies that introducing cannabis during puberty brings about long lasting changes in behaviour which persist even after administration of cannabis is stopped. These findings suggest that a similar thing may be happening, said Professor Patton.

During the teen years the parts of the brain that are involved in managing emotions are still developing rapidly and it is highly possible that heavy cannabis use at this sensitive point could have long lasting effects.

However the authors write that they cannot rule out the possibility that the factors that predispose people to use cannabis early also put them at risk for common mental disorders.

These common factors might include biological, personality, social and environmental factors, or a combination of these factors. This is a plausible hypothesis because social disadvantage is more common among persons who are problematic substance users and who meet criteria for common mental disorders, they write.

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User comments

Or maybe seeing their friends busted, the stigma from friends and family because of false information, the inflated cost of an drug due to its legality. Maybe its the drug tests businesses ask for or just the paranoia of being watched by DEA.

All good reasons to be anxious, and all can be solved with education and law reform.

Bob...if you took the cannabis at 20...and had no anxiety attacks until 29...How did you know at 20 you had anxiety attacks? Or that they were coming?I mean...if you already had anxiety attacks at 20, taking the heavy doses of cannabis would NOT have made you better if attacks got worse at 29...you would be worthless for the experiment!So no point in talking cannabis use to someone already messed up..!

this 'research' is unbelievably stupid. as anyone can tell you---people with high anxiety are drawn towards cannabis use because it's an anti-anxiety drug, just like benzo diazepans. i bet they didn't release their research yet on how people who were formerly benzo users, tend to have anxiety later in life. it's because they always had it.

"...But the really striking finding say the authors is the persistent association between frequent teenage cannabis use and adult anxiety disorders up to a decade after cannabis use has ceased.Read more at: http://medicalxpr...html#jCp

Dude...they QUIT the cannabis for ten years...! The anxiety you declare must have been present...somehow was endurable for TEN years without Cannabis...what happened?

You said people are drawn to it who need it...what pushed the 'quit-for-ten-years-button? High Unemployment? Wha?

teenagers... common sense vs training are causing mental conflicts in many teenagers. a world where religion(fantasy) and money(domination) is attacking the future of human existence. the problems are money and religion, everything that stems from money and religion are nothing but symptoms of. as long as money and religion exists, there will be ulterior agendas. pot causes anxiety? money and religion causes more anxiety than anything.

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